Mechanical pencil



E. G. E. HOGNER I 'Feb; 11, 1930.

MECHANICAL PENCIL Filed Jan. 15, 1929 Patented Feb. 11, 19 30 UNITEDSTATES PATENT OFFICE I um GUSTAF EVALD noeivnn, or srooKI-iomv SWEDENMECHANICAL PENCIL, Application filed January 15, 1929. Serial No.332,576.

This invention relates to mechanical pencils and more particularly to animproved step by step feeding mechanism for the lead or crayon in suchpencils.

Thechief object of the invention is to provide improved means of thiskind in which the pusher is automatically released at the end of itsadvancing movement after a lead hasbeen entirely pushed out or consumedand afiter returning to its starting position is again brought intooperative engagement withthe step by step feeding mechanism.

The invention consists, chiefly, in a step by step feeding mechanism forthe lead or crayon, comprising a stationary and a slidable rack, meansfor reciprocating said slidable rack, a slide, pawls carried by saidslide and normally engaging said racks, a pusher connected to the slide,a control-member for lindrical shape is provided having a vertical.series of teeth or a rack 8 cut in its inner wall. A second inner sleeve4 of semicircular cylindric shape is also provided in the outer sleeve 1and has likewise a vertical series of teeth or a rack 5cut in its innerside-wall. The sleeves 2 and 4 together form a cylinder and the racks 3and 5 which only extend along a part of the length of the respectivesleeves are placed diametrically opposite to each other (Fig. 5). Thesleeve 2is detachably attached to the sleeve 1 by means of a bayonetjoint comprising a pin6 engaging a groove 7 while the sleeve 4 isslidable in the saidouter sleeve 1 and thus also slidable in relation tothe sleeve 2. i a

The stationary inner sleeve 2 is provided at one end with a bottom 8,from which a tube 9 having an annular flange 10 extends upsaid pawlsmovably journalled in said slide, wards in the centre of the pencil. Thetube and a stop adapted to operate said control- 9 serves as a stopmember for releasing the .member in the lowermost position of the feedmechanism in its lowermost posit-ion.

slide so as to release the pawls from engage- In its other end thesleeve 2 carries a cylinment with the racks. i dricstop or end member 11secured to it by In the accompanying drawings one embodmeans of screws8? or the like. The slidable iment of my invention is shown. innersleeve 4 has at its lower end a bottom Fig. 1 shows an improved pencilaccord 12 containing an opening, which fits onthe ing to my invention,partly in longitudinal tube 9 but cannot pass the flange 10. Thesection. upper end of the said sleeve 4 is formed with Fig. 2 shows .aportion of the pencil in a projection 13 extending laterally andhavlongitudinal section at right angles to the ing an annular flange 14on its upper side. A sectionin Fig. 1. screw 15 extendsthrough a hole inthe said Fig.3 shows a portion of the pencil in the projection 13 and isscrewed into the stop or same longitudinal section as shown in Fig. 1end member 11. The head of the screw 15 to illustrate the position ofthe parts immeforms a stop for the sleeve 4 to check its updiately afterthe pusher has been released. ward movement. A spring 16 is providedFigs. 4 and 5 are cross-sections on a larger between the bottoms8 and 12and presses the scale on the lines IV-IV and VV in sleeve 4 upwards,thus causing the projection Fig. 1. i 13 normally to rest against thehead of the Fig. 6 is longitudinal section of a porsaid screw 15.Longitudinal recesses 17 are tion of the pencil illustrating a modifiedemmade in the outer wall of the sleeve 4 to rebodiment of the pawls andtheir control memduce its friction when it slides in the sleeve ber. ai 1. On the annular flange 14 a holder 18 for Fig. 7 illustrates theposition'of the parts an eraser 19. isprovided which is covered by shownin Fig.6 immediately after the pusher a removable cap 20 rests upon theprohas been released. jection 13 by means of a shoulder.

Referring now to Figs. 1 to 5 of the draw- In the cylindricchannel'formed between ings 1. indicates an outer sleeve of well-knownthe sleeves 2 and 4 a slide 21 is provided havtype for mechanicalpencils. In this outer ing a pusher-22 secured thereto. The said sleeve1 an inner sleeve 2 of semicircular cypusher is placed in the axis ofthe pencil and is guided by the tube 9. The slide 21 has a recess orgroove 23 extending through it and forming two longitudinal openings inthe periphery thereof diametrically opposite to each other. In the saidrecess 23 two pawls 24 and 24 rotatable on pins 25 are provided, saidpawls projecting through the said opposite openings and engaging theracks 3 and 5, respectively. A pin 26 (Fig. 5) engaging a groove 27 inthe inner wall of the sleeve2'is provided on the outer side of the[slide 21 to guide the latter in such manner that the pawls 24 and 24are always right in'front of the racks 3 and 5. The pawls 24 and 24 areconnected by a spring 28 tending to withdraw them from their engagementwith the racks 3 and 5. The inward movement of the pawls 24 and 24" islimited by pins 29.

A control-member or rod 30 is slidably journalled in the slide 21between the pawls 24 and 24". On the upper portion of the saidcontrol-member which projects above the slide 21 a collar 31 is fixedlimiting the movement of the said control-member downwards in relationto the slide 21. The control member 30 is forked in its lower portion(Fig. 2) and the prongs thereof enclose the spring 28 and projectdownwards below the slide 21 on both sides of the pusher 22. The upperedges of the said prongs are checked by shoulders 32 of the slide 21when the controlanember is moved upwards, the movement of the latterthus being limited upwards as well as downwards. Two springs 33 aresecured to the control-member and engage the back sides of the pawls 24and 24 in the lowest position of the control-member to press themtowards the racks 3 and 5 against the action of the spring 28.Immediately above the points in which the springs 33 engage the pawls 24and 24* in the said lowest position (Fig. l) of the control-member 30the said pawls are provided with steep noses or shoulders 34. A spiralspring 35 is provided between the slide 21 and the bottom 12 to pressthe said slideupwards in the direction from the point of the pencil. Oneor more spring-pressed buffers 36 may be provided in the projection 11to receive the shock when the slide is returned by the spring 35. Theleads or crayons to be fed are contained in a suitable magazine 37, forinstance, of the revolving type. V

The device now described works as follows:

To feed the lead the cap 20'is pressed downwards pushing in its turnthesleeve 4 in the same direction until the bottom 12 is checked by theflange 10 or the projection 13 is stopped by the stop or end member 11and the upper edges of the sleeves. 1 and 2. The stroke of the sleeve 4is substantially equal to the pitch of the racks 3 and 5. hen the sleeve4 is thus pushed downwards the slide 21 is also pushed downwards by thepawl 24 engaging the rack 5- The pusher 22 which is secured to the saidslide 21 is consequently also pushed down the same distance and feeds inits turn the lead from the magazine 37 before it. At this movement theother pawl 24 drags over the adjacent tooth of the rack 3 compressingthe corresponding spring 33 and is caused by the said spring to engagethe next tooth after the advancing movement has been completed. The cap20 is now released whereupon the spring 16 restores the sleeve 4 as wellas the cap 20 to their starting positions. During this movement theslide 21 is kept in position in relation to the sleeve 2 by the pawl 24engaging the rack 3 while the pawl 24 drags over the rack 5 until itengages the next tooth when the return movement is finished. By pressingand releasing the cap 20 in this manner the lead before the pusher isfed successively until it has been entirely consumed. The slide 21 thenreaches the lowest point of its path and the prongs of the forkedportion of the control-member 30 are checked by the upper end of thetube 9. The control-member 30 is thereby pushed upwards in relation tothe slide 21 until the two springs 33 pass the projections 34 on thepawls 24 and 24 The spring 28 now withdraws the pawls 24, 24 from theracks 3 and 5 respectively, the different parts thereafter having thepositions shown in Fig. 3. The slide 21 thus released is now restored bythe spring 35 to its starting position in the uppermost portion of thepencil body. At the end of this movement the upper portion of thecontrol-member 30 is checked by the projection 11 and the saidcontrol-member is pushed back in relation to the slide 21 so that thesprings 33 pass by the projections 34 and again bring the pawls 24, 24to engage the racks 3 and 5. The control-member 30 is then kept in itsnormal position by springs 33 engaging the slanting or concave backsides of the pawls 24, 24 below the projections 34. Now the feeding canbe started again as described above.

In the modified embodiment shown in Figs. (5 and 7 a wedge-shapedportion 38 of the control-member 3O converging upwards in the directionfrom the point of the pencil is used for releasing the pawls 24, 24.When the prongs of the control-member 30 are checked by the tube 9 atthe lowest end of the path of the slide 21 the wedge 38 is pressedupwards, thus pushing the lower ends of the pawls 24, 24 apart. Theupper portions of the said pawls are thereby withdrawn from theirengagement with the racks 3 and 5 and release the slide 21 which isrestored to its starting position by the spring 35 as described above.

To put the mechanism apart, for instance when the magazine 37 is to befilled the bayonet joint 6, 7 is opened and the sleeves 2 and 4 aswellas the magazine are drawn out from the outer sleeve 1. V

The magazine 37 may be of any suitable construction and forms no part ofthis invention. The mechanism above described can, if desired, be usedWithout any magazine whatever. In this latter case the leads are placedby hand before the pusher and then successively fed, as describe What Iclaim is:

1. In a mechanical pencil, a step by step feeding mechanism for the leador crayon,

comprising a stationary and a slidable rack,

a means for reciprocating said slidable rack, a slide, pawls carried bysaid slide and normally engaging said racks, a pusher connected to theslide, a control-member for said pawls movably journalled in the slide,and a stop member adapted to operate said control,- member in thelowermost position of the slide so as to release the pawlsfromjengagement with the racks.

2. Ina mechanical pencil, a step by step feedingmechanism for the leador crayon, comprising a stationary and a slidable rack, means forreciprocating said slidable rack, a slide, pawls carried by said slideand nor-.

mally engaging said racks, a pusher carried by said slide, a controlmember for said pawls movably journalled in the slide, a stop memberadapted to operate said control member in the lowermost position of theslide so as to release the pawls from engagement with the racks, and aspring for returning the slide to its uppermost position.

3. In a mechanical pencil, a step by step feeding mechanism for the leador crayon, comprising a stationary and a slidable rack, means forreciprocating said slidable rack, a slide, pawls carried by said slideand normally engaging said racks, a pusher connected to the slide, acontrol-member for said pawls movably journalled in the slide, and

stop members adapted to operate said control-member in the end positionsof the slide so as to bring the awls in and out of engagement with therac rs. 4. In a mechanical pencil, a step by step feeding mechanism forthe lead or crayon, comprising a stationary and a slidable rack, meansfor reciprocating said slidable rack, a slide between said racks, pawlscarried by 5 said slide and normally engaging said racks, a pusherconencted to the slide, a control rod movably journalled in the slide,springs carried by said control rod and adapted to operate the pawls,and stop members adapted to operate said control rod in the endpositions of the slide so as to bring the awls in and out of engagementwith the rac s.

In testimony whereof I have signed my name. EINAR GUSTAF EVALD accuse.

